{
  "id": 7845958,
  "title": "Alpenglow Finality in Numbers: 60%, 80%, 250 ms, 800 ms",
  "url": "https://urgent.news/2026/09/16/alpenglow-finality-in-numbers-60-80-250-ms-800-ms",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-16T18:41:03.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/sulimanmukhtar/alpenglow-finality-in-numbers-60-80-250-ms-800-ms-31b5"
  },
  "original_language": "en",
  "account": "Alpenglow, a recent update to the Solana blockchain, replaces the previous system of voting and finality with a new approach focused on certificates and thresholds. Under Alpenglow, a block is considered confirmed once two-thirds (60%) of the network's stake has signed off on it at least once, while finality is achieved when 60% of the stake signs a final block, which then becomes immutable even if subsequent blocks are built on top of it. This finality threshold is lower than the current two-thirds because Alpenglow's safety budget is spread differently, allowing for more Byzantine failures and network downtime without compromising security.\n\nA key aspect of Alpenglow is the reduction of the time it takes for a block to become final. Previously, a block required 32 confirmations, taking around twelve seconds. With Alpenglow, once a block reaches the finalize stage with 60% validation, it becomes final in just one additional step, taking approximately 800 milliseconds. This reduction in time is aimed at improving transaction finality and reducing latency for users.\n\nThe protocol's design constants include DELTA, which is the maximum time (250 milliseconds) a message takes to travel across the network under normal conditions, and DELTA_TIMEOUT, set at 400 milliseconds. These constants help determine when a leader who fails to produce blocks should be skipped, and this process takes about 800 milliseconds. This change in timing aims to improve overall network performance and reduce the time it takes for transactions to be finalized.\n\nAn important point to note is that votes are no longer transactions under Alpenglow. Instead, they are sent as dedicated QUIC datagrams between validators. This change affects the economics of running a validator, as it removes vote fees and requires validators to budget for six packets per slot plus a refresh batch. Additionally, there's a migration window of 5,000 slots (about 33 minutes) where the network operates differently, and validators may produce vote-only blocks without committing to a final state.\n\nIn summary, Alpenglow introduces significant changes to the Solana blockchain, focusing on faster finality, lower thresholds for block validation, and new methods for voting and transaction processing. These changes aim to improve the overall efficiency and performance of the network, although they also bring new complexities and considerations for users and validators to navigate.",
  "summary": "Originally published on xroot.dev . Ask five Solana traders how long a transaction takes to become final and you will get five answers, all of them \"about a second\" and none of them a definition. Today \"confirmed\" means two-thirds of stake voted on the block at least once, and \"finalized\" means 32 blocks were built on top of it — a depth, not a time. A wallet turns the tick green somewhere in…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}